Simple Calculations in Photon Energy and Work Function Quiz

11th Grade

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By Thames

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| Questions: 20 | Updated: Mar 8, 2026

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1. Photon energy increases when:

Wavelength increases

Frequency increases

Intensity increases

Distance increases

Concept: photon energy dependence. e=hf; higher f → higher e. Frequency directly increases energy per photon, while intensity changes how many photons arrive.

Explanation

Concept: photon energy dependence. e=hf; higher f → higher e. Frequency directly increases energy per photon, while intensity changes how many photons arrive.

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About This Quiz

Simple Calculations In Photon Energy and Work Function Quiz - Quiz

This assessment focuses on calculations related to photon energy and work functions, evaluating your understanding of key concepts in quantum physics. Learners will apply formulas to determine energy values and work functions, enhancing their grasp of light-matter interactions. This knowledge is essential for anyone studying physics or related fields, as... see moreit lays the groundwork for more advanced topics in quantum mechanics. see less

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2. A shorter wavelength corresponds to a higher frequency.

True

False

Concept: wave relation c=fλ. c=fλ; if λ decreases, f increases. Since c is constant for light in vacuum, wavelength and frequency are inversely related.

Explanation

Concept: wave relation c=fλ. c=fλ; if λ decreases, f increases. Since c is constant for light in vacuum, wavelength and frequency are inversely related.

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3. If a metal’s work function is 2.0 eV and the photon energy is 2.5 eV, the maximum kinetic energy is:

0 eV

0.2 eV

0.5 eV

4.5 eV

Concept: energy balance using k_max=e-φ. k_max=e-φ=2.5-2.0=0.5 eV. The work function is the 'cost' to escape, and the remainder becomes kinetic energy.

Explanation

Concept: energy balance using k_max=e-φ. k_max=e-φ=2.5-2.0=0.5 eV. The work function is the 'cost' to escape, and the remainder becomes kinetic energy.

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4. If e_photon < φ, then photoelectrons are ______.

Concept: threshold requirement. Photon doesn’t provide enough energy. Without meeting the work function, the electron cannot escape the surface.

Explanation

Concept: threshold requirement. Photon doesn’t provide enough energy. Without meeting the work function, the electron cannot escape the surface.

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5. If φ=3.0 eV and photon energy is 2.8 eV, electrons are:

Emitted with 0.2 eV

Emitted with 5.8 eV

Not emitted

Emitted with negative ke

Concept: comparing photon energy to work function. Not enough energy to escape. Because 2.8 eV is below 3.0 eV, emission does not occur at all.

Explanation

Concept: comparing photon energy to work function. Not enough energy to escape. Because 2.8 eV is below 3.0 eV, emission does not occur at all.

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6. If photon energy equals the work function, electrons can be emitted with nearly zero ke.

True

False

Concept: threshold (just-emitted) case. It’s the threshold case. All photon energy is used to free the electron, leaving essentially no kinetic energy.

Explanation

Concept: threshold (just-emitted) case. It’s the threshold case. All photon energy is used to free the electron, leaving essentially no kinetic energy.

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7. Which change increases photon energy?

Using longer wavelength light

Using higher frequency light

Lowering frequency

Increasing intensity only

Concept: frequency sets photon energy. Photon energy depends on frequency. Increasing intensity increases photon number, not photon energy.

Explanation

Concept: frequency sets photon energy. Photon energy depends on frequency. Increasing intensity increases photon number, not photon energy.

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8. A photon has energy e=4.0 eV and a metal has φ=2.5 eV. The maximum ke is:

6.5 eV

1.5 eV

1.0 eV

0 eV

Concept: subtracting the work function. 4.0-2.5=1.5 eV. The remaining energy after escape appears as the maximum kinetic energy.

Explanation

Concept: subtracting the work function. 4.0-2.5=1.5 eV. The remaining energy after escape appears as the maximum kinetic energy.

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9. Increasing intensity at fixed frequency changes the energy per photon.

True

False

Concept: intensity vs photon energy. It changes the number of photons, not energy per photon. Photon energy stays set by frequency through e=hf.

Explanation

Concept: intensity vs photon energy. It changes the number of photons, not energy per photon. Photon energy stays set by frequency through e=hf.

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10. If light above threshold shines on a metal and you double the intensity, the number of emitted electrons per second will most likely:

Halve

Stay the same

Increase (often roughly proportional)

Become zero

Concept: emission rate scales with photon flux. More photons → more photoelectrons. With the same frequency, each photon can eject at most one electron, so a higher photon rate raises emission rate.

Explanation

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11. The graph of k_max vs frequency is approximately a straight line with slope ______.

Concept: linear relationship in the photoelectric equation. k_max=hf-φ is linear in f. The slope is Planck’s constant, showing a direct proportionality between frequency and maximum kinetic energy.

Explanation

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12. On a k_max vs f graph, the threshold frequency is where:

Intensity is maximum

K_max=0

K_max is negative

F=0

Concept: identifying threshold on a graph. At threshold, electrons just escape with zero ke. This is the point where the line meets the frequency axis.

Explanation

Concept: identifying threshold on a graph. At threshold, electrons just escape with zero ke. This is the point where the line meets the frequency axis.

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13. A higher work function shifts the threshold frequency to a higher value.

True

False

Concept: work function effect on threshold. More energy needed → higher f. Since threshold occurs when hf=φ, larger φ means larger threshold frequency.

Explanation

Concept: work function effect on threshold. More energy needed → higher f. Since threshold occurs when hf=φ, larger φ means larger threshold frequency.

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14. Two experiments use the same metal. Experiment A uses higher frequency light than B (both above threshold). Compared with B, A produces electrons with:

Lower ke

Higher maximum ke

Same maximum ke

No electrons

Concept: frequency increases maximum ke. Higher frequency → higher ke. More photon energy remains after subtracting the same work function.

Explanation

Concept: frequency increases maximum ke. Higher frequency → higher ke. More photon energy remains after subtracting the same work function.

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15. Which are consistent with the photon model? (Select multiple answers)

Threshold frequency exists

Electron ke depends on frequency

Electron ke depends mainly on intensity

Increasing intensity increases emission rate

Concept: photon model predictions. a, b, d match experiments; c is a classical mistake. Intensity increases how many electrons are emitted, but frequency controls their maximum kinetic energy.

Explanation

Concept: photon model predictions. a, b, d match experiments; c is a classical mistake. Intensity increases how many electrons are emitted, but frequency controls their maximum kinetic energy.

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16. The work function depends on the metal surface/material.

True

False

Concept: material dependence of φ. Different metals have different φ. Surface conditions can also affect the effective work function, so it is tied to the surface/material.

Explanation

Concept: material dependence of φ. Different metals have different φ. Surface conditions can also affect the effective work function, so it is tied to the surface/material.

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17. If a metal is not emitting electrons, the best first change is to:

Lower frequency further

Increase frequency

Reduce intensity

Cool the lamp

Concept: overcoming the work function. Emission requires photon energy above the work function. Increasing frequency increases photon energy and can push it above the threshold.

Explanation

Concept: overcoming the work function. Emission requires photon energy above the work function. Increasing frequency increases photon energy and can push it above the threshold.

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18. If you want electrons with greater ke but the same emission rate, you should primarily:

Increase intensity only

Increase frequency and adjust intensity if needed

Change nothing

Use lower frequency

Concept: separating controls (frequency vs intensity). Frequency sets ke; intensity sets rate. If frequency is increased, you may adjust intensity to keep the emission rate similar.

Explanation

Concept: separating controls (frequency vs intensity). Frequency sets ke; intensity sets rate. If frequency is increased, you may adjust intensity to keep the emission rate similar.

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19. Photoelectric effect supports quantization of light energy.

True

False

Concept: quantization evidence. Photon concept explains results. The threshold effect and the frequency dependence of electron energy point to discrete energy packets.

Explanation

Concept: quantization evidence. Photon concept explains results. The threshold effect and the frequency dependence of electron energy point to discrete energy packets.

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20. Best grade 11 summary: photoelectric effect is described by:

K_max=φ-hf

K_max=hf-φ

K_max=iφ

K_max=c/λ

Concept: correct photoelectric equation. Correct relationship is hf-φ. The photon provides energy hf, the work function φ is required to escape, and the remainder becomes kinetic energy.

Explanation

Concept: correct photoelectric equation. Correct relationship is hf-φ. The photon provides energy hf, the work function φ is required to escape, and the remainder becomes kinetic energy.

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